High Density Polyethylene (HDPE) Sheet . High Density Polyethylene (HDPE) Sheet. This sheet can be heat formed, shaped, and welded to fabricate ducts, hoods, and much more. The material cannot be cemented, but it is easily welded with a plastic welder. It can be cut with a carbide-tipped saw blade and drilled with regular metal bits. Translucent white.